Air-engine



P. SHAW.

HOT AIR ENGINE.

Patented May 2, 1854.

UNITED STATES PATENT OFFICE.

PHILANDER SHAW, OF EAST ABINGTON, MASSACHUSETTS.

AIR-ENGINE.

Specification forming part of Letters Patent No. 10,868, dated May .2,1854.; Reissued July 17,

1 To all whom it may concern clear, and exactdescription, referencebeing? had to the annexed drawings, making part of this specification,in which Figure 1 is a plan of the engine; Fig. 2, asectionon the lineWV, WV, of Figs. 3 and 4c,

the shell of the auxiliary heater being re- 'moved to showthe partswithin; Fig. 3, a

section on the line Y, Y, of Fig. 1; Fig. 4, a

f section on X, X, of Fig. 1; Fig. 5, an en- .larged section of the mainheater on Z, Z,

the heater and fire box, and which opens at the top into the'chimney orsmoke box E of Fig. 2. e e

The nature of my invention consists firstly in the employment ofauxiliary heaters, which are so connected together and with each otherby means of valves that the air for the supply of the engine shall bepumped f in against the minimum pressure within themain heater, while itis worked off at the max mum pressure.

My invention also consists in passing the exhaust air from the cylindertogether with the smoke and heated gases from the furnace through theauxiliary heaters in one di- -rection while the air for the supply ofthe engine is caused to pass in the contrary direction through tubeswithin these auxiliary heaters by which means the heat is extracted fromthe. exhaust air and smoke and transferred to the air on its way fromthe air pumped to the heater.

Great inconvenience has heretofore been experienced in the working ofhot-air engines from the difiiculty of obtaining a packing that willresist the great tempera- .ture to which .thepiston is liable to beraised; to remedy this inconvenience I have adopted the plan ofrefrigerating the piston by means of a constant stream of cold Waterwhich is made to circulate through its interior and thus preserve it ata temperature not exceeding that of boiling water.

To enable others skilled in the art to make and use my invention I willproceed to describe the method which I have adopted of carrying it out,describing first my separate improvements and finally the generaloperation of the complete engine.

A is the mainheaterinto which the air is received from the auxiliaryheaters, and in which it receives a final heating preparat-ory to beingadmitted to the working cylinder.

B is the fire box; C, the ash nace beneath the heater A. I

a are vertical tubes which pass. entirely through the heater and throughwhich the smoke and burning gases from the furnace pass. a

.D, is a chamber which entirely surrounds pit of the furand communicateswith the chamber beneath the furnace through the openings cl, in itsbottom plate, the object of which will be explained hereafter.

F is an air pipe of communication between the auxiliary and the mainheaters which isentirely surrounded by the smoke flue G, and isfurnished with a valve 19, opening downward at its lower extremity.

H, is the auxiliary heater,'which is divided into three sections orminor heaters H, H, H. These sections are separated from each other andfrom the ends of the heater by chambers I, I, I, 1, formed by closefitting partitions the chambers I, I I I, communicating with each otherthrough the tubes 0, c, 0, K, K, K. The smoke fro-m the furnace entersthrough the pipe G, into the chamber 1', thence it passes through thetubes 0, K, into the chamber I", thence through the tubes K, 0, into thechamber I, thence through the tubes K, 0, into the chamber I, whence itpasses off by the chimney M.

By the arrangement above explained it will be perceived that thecompartments H H H are entirely shut off from the chambers I, I, I, I,and from the smoke flues c, and K, which pass through them. They howevercommunicate with each other through the short tubes L, L, these tubesare fitted at their advance ends with valves 6, e, the air from theforce pump is admitted into these compartments in succession, passingthrough the tubes L and L, and the'valves e, e, in a manner which willbe hereafter more fully described.

N, is the working cylinder; 0, the hot-air box which communicates withthe heater A through the pipe P.

Q, is the hollow piston, the piston rod of which is also hollow as seenin Fig. 2.

g, isa tube inclosed within the hollow piston rod, and penetrating it atabout the point h. 1 V

R, is a receptacle for water.

S, S, are india rubber tubes from the top and bottom of thisreceptaclewhich communicate one with the interior of the hollow piston,and the other with the small tube inclosed therein. By this means thewater from the receptacle R, is caused to circulate continually throughthe hollow piston which is thus prevented from becoming injuriouslyheated as before mentioned.

T, is the discharge pipe from the working cylinder, which is made toenter the ash pit C, immediately beneath the grate bars, all theadvantages resulting from urging the fire with heated air are thusobtained. The excess of the exhaust air not required by the;

fire, passes through the openings d, into the chamber D, which incasesthe furnace, and

abled to economize the heat which would otherwise be radiated from theoutside of the furnace.

' The object of thus exhausting the hot air from the cylinder into theash pit beneath .the furnace is twofold;firstly, the fire is urged withheated air ;secondly, such portion of the exhaust air as is not thusconsumed passes with the products of the furnace into the auxiliaryheaters where it is refrigerated by the fresh air enteringfrom the forcepump in a manner that will be presently explained.

V, is the force pump for supplying the heater with air, the area of itspiston being about one half that of the working piston. Air is admittedto this pump through the valves 9, and escapes through valves in the topof the cylinder into the chamber h, thence it passes by the pipe A, intothe compartment H, of the auxiliary heater; here it circulates round theoutside of the smoke passages and tubes 0, K, and passes (when thepressure is removed from the main heater in the manner which will behereafter explained) through the short communication pipes L, and valves6, into the compartment H, here it again circulates around the smokepipes c, K, and through the pipe L and valve 6 into the compartmentH,from this compartment it passes through the pipe F, and valve 5, intothe heater A It is evident that the auxiliary heater may consist of oneor more compartments, there being always a valve communication betweenthe last of such compartments and the main heater.

Operation: The air within the main heater A, as it expands closes thevalve 6, which thus prevents it from returning through the pipe F intothe auxiliary heater H, a charge is then admitted to the workingcylinder, the

capacity of the heater A being such with relation to the workingcylinder that when cut off at stroke or thereabouts the pressure withinthe heater A shall be very much reduced, the valves 6, c, 0, then open,or as soon as the pressure in the compartments is reduced below what itis in the one behind it,and the pressure for'an'instant is the same inall the compartments. The expansion caused by the extreme heat withinthe heater A soon closes the valve 6, the valves 0, a, being in likemanner closed as the heat within the compartment H is greater than thatwithin H, and so on, it being nearer to the furnace. The pressure WithinH, thus always remains at very near the minimum, and as the air ispumped into this compartment it is evident that it is only resisted bythis minimum pressure, while it is worked oif from the main heater A atits maximum as before stated enters the close ash pit G,

and the fire is thus urged by a hot blast.

That portion of the exhaust air not required by the fire passes off withthe products of combustion, and is refrigerated in the auxiliary heaterH, by the entering air. The exhaust air may be made to enter the auxiliary heater with the smoke from the furnace, and thus a portion of theadvantages above described will be secured, but I prefer the exhaustbeneath the fire for the reasons already set forth.

Several heaters and auxiliary heaters may be adapted to a single engine,a charge of air being taken from each in succession.

l/Vhat I claim as my invention and desire to secure by Letters Patentis- 1. The within described auxiliary heater constructed and arranged asset forth, the exhaust air and the products of combustion being passedthrough in one direction while in against a pressure much less than thatat herein described of the tubes Within the piswhich it is Worked offfrom the main heater ton rod, the reservoir R and the india rub- 10 a asexplained. ,ber tubes S, S, for the purpose set forth.

5 the purpose of refrigerating the cylinder or piston of hot air orother engines, but What Witnesses: I do claim as my invention and desireto se- SAM COOPER, cure by Letters Patent is the arrangement JOHN S.GLOW.

not claim the use Of Cold Water fOI [Fms'r PRINTED 1913.]

